Inner walls consisting of, for example, dry wall panels, are secured to outer walls made of concrete block, bricks, or stones. Till now, it was necessary to first secure furring or strips to the outer wall by the use of nails explosively shot through the furring and into the outer wall and then to nail or screw the dry wall panels to the furring. The furring leaves room for insulation between the two walls. However, use of explosively-shot nails is expensive and requires a special gun.